A standard reusable transport/storage box, typically made of injection-molded plastic, has a floor, a pair of upstanding long side walls, and a pair of short upstanding end walls that bridge ends of the side walls. The walls are formed as isosceles trapezoids with their larger ends up so that the boxes can be nested. As described in EP 1,428,764 and U.S. Pat. No. D493,282 of DuBois two identical cover halves are secured by hinges to upper edges of the side walls. These cover halves can be pivoted between a closed position in which they are horizontal and coplanar and their toothed outer edges fit together to close the top of the box and an open position in which each cover half hangs down from the respective hinge against the respective side wall of the box.
German 104,136 of Oppenländer describes latches each having a slidable latch member that serves to secure the respective cover half to the upper edge of the box in the closed positions. These latches are constructed such that when the cover halves are moved into the closed position, they fit into and mate with holes on the upper end-wall edges. To release the cover halves, it is necessary to manually slide the latches into a releasing position, then owing up the cover halves.
A problem with such boxes is that, when they are open, the pendant cover halves are unstable. So long as the boxes are sitting upright, these cover halves hang straight down, out of the way, but when they are not level, the cover halves can move into inconvenient positions. Furthermore to nest the boxes together when empty, as is done for instance when they are being returned, it is necessary to carefully press the two cover halves of one box against the respective side cover halves before fitting the one box into another box. If the side cover halves are not positioned flatly against the respective side cover halves, the boxes cannot be nested.